When it launched, the iPhone instantly became the hip high-tech accessory. Since then, the little gadget that could has become something more: From applications that dish the latest runway news to ones that help mix and match your wardrobe, it's also become a powerful pocket-size tool for the stylista.

From Vogue magazine to Dolce & Gabbana, just about every designer and retailer worth their Jimmy Choos have launched an iPhone application.

Then again, you don't need to be fashion forward to see the appeal. Since opening the doors to its App Store in July 2008, Apple's 75 million worldwide iPod Touch and iPhone users have downloaded more than 3 billion apps.

The new iPad, with about 150,000 apps available from the App Store, can only heighten their allure. Clearly, apps are a fashion "do."

Fashion and shopping applications aren't one of the store's 20 categories, but several are at the top of its most popular lifestyle downloads. And they vary widely. Some designers offer a digital lookbook of its current line that fashionistas can thumb through. Others, such as Miss Sixty, give special discounts to customers who download its iPhone apps. Still more help you comparison shop, organize your wardrobe, find the perfect gift, stay tuned to the latest fashion scoops and in the case of FastMall, navigate large shopping malls.

They've also been handy during fashion weeks, with designers, magazines and retailers offering tickets, schedules and exclusives through their iPhone apps.

Megaro is developing an iPhone app that will help users make the best of what's already in their closet. "Fashion is at our finger tips," he said.

Macala Wright, an independent fashion marketing consultant, uses Stylish Girl, a closet organizing app, to keep track of the items she owns and the ones she's looking to purchase. On a recent business trip, it helped her match a pair of eco-friendly, recycled gold earrings with a necklace from a different, but similarly styled designer.

"Sometimes I can picture it in my mind but I can't remember the exact details," she said. Just being able to find a photo easily helps her see if the two items form a cohesive look while she shops.

"People are downloading apps that are relevant to their life," she said. "When you shop, something like this app is very useful."

Lucky At Your Service

Why we like it: With the hard copy of Lucky magazine, you flip through the pages and tag the items you'd like to buy - the magazine even supplies tape flags. Its iPhone app takes it a step further, offering instant gratification at your fingertips. Browse the products featured in the magazine and if you want it, the app pinpoints your location and finds nearby stores that have it. You can then put it on hold and pick it up. Unfortunately, Lucky's concierge service isn't available for all of its products and at times can be buggy.

Cost: Free

Others to consider: Vogue spent more than six months designing its app, which it introduced in late February. The free application identifies the current trends - this month, it includes natural shades and the statement sandal - and helps you adapt it to your wardrobe. Like Lucky At Your Service, Seventeen Fashion Finder helps you put favorite items on hold at a nearby store, though its catalog is smaller. The Elle Shopping Guidereviews and maps out recommended boutiques based on your location, although its listings are limited only to San Francisco proper.

The Weather Stylist

One of several weather-related fashion applications, the Weather Stylist uses your location to give you the day's forecast and suggest a few appropriate outfits. Naturally, if you like what you see, it helps you buy the pieces online. But I'm not sure if this application - or any of its rivals - really understands the Bay Area's need for layering.

Cost: $1.99

Others to consider: The Feather Report, which is free, also suggests weather-appropriate looks. It also has an added feature that helps you find an outfit based on the temperature, occasion and your body type.

Stylish Girl/Cool Guy

A tool for the hyper-organized fashionista, Stylish Girl and the corresponding Cool Guy helps you see what's in your closet and come up with new outfits. Take pictures of your wardrobe and then scroll through them slot machine style to match your tops, bottoms, accessories and shoes. The app also includes a shopping feature so that you can add your dream item to your digital closet or buy it online to complete your look. We knew those strappy Manolo Blahnik heels would look good with our outfit - and now we can prove it.

Cost: Free.

Style.com

The Style.com app feeds you the latest news in the fashion industry, with video clips from the runway, photos and blurbs from the party scene and a large library of the major designers' latest collections.

Cost: Free

Others to consider: Chictopia, a free app, aggregates photos and posts from a series of fashion blogs, which you can read from within the app instead of having to upload each site.

Gap StyleMixer

Ignore the outfit-creating tool and keep an eye on the application's store finder. It regularly offers special discounts to users of the app who happen to be near a Gap store.

Cost: Free

Others to consider: For some guilty pleasure, the luxury brands have it. Chanel's application includes news from the designer, video from its runway show and photos of its current looks. A separate Chanel app, the Lovely Game, turns the iPhone into a Vegas slot machine that you shake to form a picture of one of its signature items. Only problem is, unlike a real slot machine, it can get old quickly. With Donna Karan's app, you can submit a question to the designer and read entries from her journal.